UWorld_3.1 Flashcards Preview

USMLE Step 1 > UWorld_3.1 > Flashcards

Flashcards in UWorld_3.1 Deck (22)
Loading flashcards...

Osteocytes connected to each other by:

gap jxns


Tight jxn characteristics/locations

  • "zona occludens"
  • @ apex of glandular cells
  • tight jxns = two closely adherent cytoplasmic membranes w/out intervening space
    • first component of a jxnl complex


Desmosomes characteristics/locations

  • desmosomes = small, circular, adherent patches
    • circumferentially placed around cells
    • comprise the thirds component of jxnl complex
  • common @ stratified squamous epithelium
  • contribute to structural cohesion of tissue subject to mechanical stressors


Hemidesmosomes characteristics/locations

  • = half desomosomes; extend from basal surfaces of keratinocytes @ stratified squamous epithelium to attach to basal lamina


Intermediate jxns characteristics/locations

  • "zona adherens"
  • =delicate network of cytoplasmic filaments that radiate from the cell membrane to hold together adjacent cells
  • second component of jxnl component


Fxn of 99mmTc-pertechnetate scan

detects presence of gastric mucosa


Characteristics/presentation of Meckel diverticulum

  • failed obliteration of omphalomesenteric duct 
    • e.g. accumulation of 99mmTc-pertechnetate @ right lower abdominal ==> indicates gastric mucosa
  • ==> lower GI bleeding
  • ==> right lower quadrant pain
  • ==> intussusception ==> colicky abdominal pain + "currant jelly" stools


Failure of ventral dorsal pancreatic bud fusion ==>

  • formation of pancreas divisum
  • usually asymptomatic


Failure of hindgut descent along the inferior mesenteric artery ==>

  • hindgut ==> distal third of transverse colon, descending, and sigmoid colon, rectum, upper part of anal canal
  • failure of descent ==> various degrees of anal agenesis or imperforate anus


Failure of midgut rotation around the superior mesenteric artery ==>

  • ==> intestinal malrotation
  • intestine is fixed by fibrous adhesive bands ==> intestinal obstruction


Importance concept in studies looking at risk modigiers 

  • latent period
  • exposure to risk modifiers may occur a significant amount of time before the exposure's effect on the disease process
    • may have to be continued for years
  • think about latency when looking at relative risk reductions between groups experiencing a risk modifier for different periods of time


Trisomy 18 presentation

  • 2nd most common autosmal trisomy
  • face: eye defects, low-set ears, prominent occiput
  • CNS: microcephaly, NTDs, Chiari malformation, developmental disability
  • MSK: clecked hands + overlapping fingers, rocker-bottom feet, hypotonia
  • Cardiac: VSD, PDA
  • GI: Meckel's, malrotation


Deficiency of membrane attack complex ==>

  • recurrent infections by Neisseria species
  • N. meningitidis
    • high-fever, chills
    • AMS
    • petechial skin rash <== N.-induced small-vessel vasculitis
      • esp. @ palms, soles


Factors that form the membrane attack complex + fxn

  • C5b - C9
  • forms pores @ bacterial cell membrane ==> electrolyte disturbances, inflow of free water, cell lysis


Tx for N. meningitis

  • IV ceftriaxone for 2 weeks


Characteristics of Blastomycosis dermatitidis

  • dimorphic fungus
    • mold form, found in soil, organic matter, and many animals
  • ==> pulmonary infections (often chronic) in immunocompetent hosts
    • respiratory transmission
    • transforms to yeast @ lungs
    • granuloma formation
  • Dx = sputum stain with KOH ==> round yeast w/thick, doubly refractive walls + single, broad-based buds
  • endemic areas
    • Great Lakes, Mississippi & Ohio River Basin


Tx of Blastomycosis dermatitidis




Reaction formation






  • Rxn form = person does opposite (excessively) of what he/she desires; used to cover up feelings they believe to be unacceptable to society
  • Projection = transplant unacceptable impulses to another person/situation
  • Repression = unconscious removal of disturbing psych material from conscious awareness
  • ID = modeling one's behavior after someone perceived to be more powerful (e.g. abused child ==> abusing as a parent)
  • Suppression = voluntary withholding of unpleasant htoughts or feelings from one's mind
  • Displacement = transfer of impulse or desire toward a safer and less distressful object


Somatostatin from pancreas ==>

suppresion of secretin, cholecystokinin, glucagon, insulin, and gastrin


Somatostatinomas ==>

  • somatostatinoma = rare pancreatic cell tumors that arise from "delta cells"
  • ==> hyper or hypoglycemia
  • ==> steatorrhea
  • ==> suppressed cholecystokinin ==> gallbladder stones 


Characteristics of acute compartment syndrome

  • increased pressure w/in fascial compartment ==> compromised blood circulation and tissue fxn
  • develops after significant trauma
    • e.g. long-bone fractures of leg or forearm


Characteristics of Dupuytren's Contracture

  • benign, slowly progressive fibroproliferative disease of the palmar fascia
  • scarring ==> nodules on palmar fascia ==> loss of finger flexibility ==> contractures that bring the fingers into flexion

Decks in USMLE Step 1 Class (97):